The present invention generally relates to a system for transferring a liquid anesthetic agent from an anesthetic bottle to an anesthetic vaporizer. More specifically, the present invention relates to an anesthetic vaporizer filling system that includes a unique valve arrangement and keyed engagement system that prevents the anesthetic agent from being released to atmosphere during filling and insures that only the desired type of anesthetic agent can be discharged into the anesthetic vaporizer.
Anesthetic agents are typically volatile substances with relatively low boiling points and high vapor pressures. Anesthetic agents can be flammable and explosive in both their liquid and vapor states. Further, inhalation of vapor by healthcare personnel in the area near where the anesthetic agent is being used can cause drowsiness. An anesthetic agent is administered to a patient during anesthesia by means of an anesthetic vaporizer. The agent is supplied to the patient from an internal sump within the vaporizer as a vapor, while the agent is stored within the sump as a liquid. The anesthetic agent is typically mixed with oxygen and nitrous oxide prior to its delivery to the patient for inhalation.
Devices and filling systems have been designed for the transfer of the anesthetic agent from a supply container, such as an anesthetic bottle, to the vaporizer sump through a closed system that minimizes the escape of anesthetic gas to the atmosphere. These devices are designed so that during set-up and disassembly procedures, the anesthetic bottle is not open and exposed to atmosphere.
One example of such a system is shown in the Grabenkort U.S. Pat. No. 5,505,236. In this patent, the filling system lacks implementation of a filler probe seal, which in turn forces the implementation of a fill vent. The fill vent is required to prevent increased vapor pressure within the sump and filling system from causing egress of anesthetic agent between the filler probe (bottle) and filler receiver (vaporizer). As a result, the fill vent allows release of anesthetic vapor to atmosphere during the filling process (most notably when filling a vaporizer with dry sump and wick). Further, the anesthetic bottle includes a plunger that is biased by a first spring. When the anesthetic bottle is pressed into the filler of the anesthetic vaporizer, the plunger contacts the outer surface of an inlet valve member that in turn is biased to a closed position by a second spring. The first and second springs are configured such that the second spring holding the inlet valve member is weaker than the first spring biasing the plunger in the anesthetic bottle. This configuration of springs insures that the inlet valve member opens prior to anesthetic agent leaving the anesthetic bottle. Therefore, the relative spring strengths of the pair of springs in the Grabenkort reference are critical to insure that the anesthetic agent is not released to atmosphere. If the strength of either spring changes after repeated use, or if one of the springs is not properly calibrated, anesthetic vapor could be released to atmosphere. This system, therefore, has several drawbacks that need to be addressed.
Presently, many types of anesthetic agents are available for use during anesthesia. These anesthetic agents include, but are not limited, to: Enflurane, Halothane, Isoflurane and Sevoflurane. Each of these anesthetic agents has different properties and vaporizers are typically designed to deliver the anesthetic agents differently depending upon the properties of the anesthetic agent. Therefore, it is important that only the correct type of anesthetic agent is delivered to the vaporizer.
Currently, the International Standardization Organization (ISO) has developed standard 5360:1993 that mandates the inclusion of a pair of protrusions on an anesthetic agent bottle. The standard calls for a specific angle between the protrusions around the bottle that is based upon the type of anesthetic agent contained within the anesthetic bottle. Because the anesthetic container for each type of anesthetic agent has its own set of protrusions and color, and because a corresponding connector device for the anesthetic bottle fits only the type of vaporizer designed for that type of anesthetic, the probability of inadvertently using the wrong type of anesthetic in a vaporizer has been greatly reduced.
Although the anesthetic bottle may include protrusions specifically positioned based on the type of anesthetic contained within the bottle and can be emptied by keyed connector tubes, typical anesthetic bottles do not include a valve arrangement that can be used to prevent loss of the anesthetic agent to atmosphere during filling. Further, the keyed connector tubes are of a small size which reduce the rate of filling the vaporizer, and require manual operation of mechanisms to retain the keyed tubes in the vaporizer while filling, and to operate valving in the vaporizer to receive the anesthetic from the keyed connector tubes. Further, the keyed connector tubes themselves contain no valving to prevent loss of anesthetic vapor from the bottle when the bottle is not connected to the vaporizer, or the loss of liquid from the bottle if the bottle is inverted while not connected to the vaporizer. Further, due to the horizontal nature of the receiving ports in vaporizers for such keyed connector tubes, small amounts of liquid anesthetic persist in the tubing when the keyed connector tubes are disconnected from the vaporizer. This liquid anesthetic is then lost, since it is not retained either in the vaporizer or the keyed connector tubes.
Therefore, a need exists for an anesthetic vaporizer filling system that allows a bottle adapter having a unique valve assembly to be attached to the anesthetic bottle. Further, a need exists for a system having a specifically configured filling station that interacts with the bottle adapter to insure that the anesthetic agent is not released to atmosphere during the filling procedure. Further, a need exists for the filling station of the anesthetic vaporizer to have a unique configuration that receives only a specified type of anesthetic agent.
The present invention relates to a filling system for use in the delivery of a liquid anesthetic agent from an anesthetic bottle to the internal sump of an anesthetic vaporizer. The filling system includes a keyed registration system such that only the desired type of anesthetic agent can be dispensed into a particular anesthetic vaporizer. Further, the filling system of the present invention minimizes the amount of anesthetic agent released to atmosphere during the filling sequence.
The anesthetic vaporizer filling system of the present invention includes a bottle adapter that is configured for attachment to an anesthetic bottle. The bottle adapter includes internal threads that are configured to receive the threaded neck of the anesthetic bottle in conformance with the ISO 5360:1993 standard. The bottle adapter includes a pair of receiving slots positioned around its outer circumference that receive protrusions formed on the anesthetic bottle in conformance with the ISO 5360:1993 standard. The receiving slots insure that each bottle adapter is attachable only to a single, specific type of anesthetic agent.
The bottle adapter of the present invention is formed from nylon and colored in accordance with the ISO standard colors for anesthetic agents, in conformance with the ISO 5360:1993 standard. The color of the bottle adapter, and matching colored features adjacent to the filler on the vaporizer, such as covers and labels, further insure that the proper type of anesthetic agent is being delivered.
The bottle adapter includes a keyed section used to insure that only a single, correct bottle adapter can be used with an anesthetic vaporizer. The keyed section includes a pair of indexing ridges formed along its outer circumference. The first indexing ridge is located at a home position and the second indexing ridge is spaced from the first indexing ridge around the outer circumference of the keyed section by an angle xcex1. The angle xcex1 is related to the type of anesthetic agent to which the bottle adapter will be applied. In the preferred embodiment of the invention, the angle xcex1 between the pair of indexing ridges is the same as the angle between the protrusions on the anesthetic bottles, as determined by the ISO standard.
The bottle adapter includes an adapter valve assembly that is positioned within the interior of the bottle adapter. The adapter valve assembly is movable between an open position and a closed position to regulate the flow of anesthetic agent from the anesthetic bottle to which the bottle adapter is mounted. Specifically, the adapter valve assembly includes an elongated valve stem having a valve head formed on one end. The valve head includes a conical sealing surface that engages a corresponding sealing seat formed on an annular flange extending into the interior of the bottle adapter. The valve head is biased into a closed position by a spring.
The outer diameter of the bottle adapter includes a probe section. The probe section is joined to the keyed section. The probe section is defined at its outer edge by a top lip. The top lip is used to position a sealing ring surrounding the outer circumference of the probe section.
The bottle adapter of the filling system of the present invention is sized to mate with a filling station mounted to the anesthetic vaporizer. The filling station is configured to receive only one type of bottle adapter to insure that the proper anesthetic agent is delivered to the anesthetic vaporizer.
The filling station includes a filler body that is secured to a mounting block of the anesthetic vaporizer. The filler body defines an open interior that is in communication with an internal cavity formed in the mounting block. The internal cavity drains to the sump of the anesthetic vaporizer such that the anesthetic agent can be directed to the sump.
The body of the filling station includes a filler spout formed on its outer end. The filler spout includes a cylindrical outer wall having a series of indexing grooves formed therein. The indexing grooves formed on the outer wall of the filler spout are positioned at an angle relative to each other around the circumference of the filler spout. The angle between the indexing grooves is based upon the ISO standard and the type of anesthetic agent to be discharged into the anesthetic vaporizer including the filling station. Preferably, the indexing grooves each includes a recessed top edge surface that allows a user of the anesthetic vaporizer to quickly identify the position of the indexing grooves on the filling station.
The filling station includes a filler valve assembly that is movable between an open position and a closed position. When the filler valve assembly is in the closed position, anesthetic agent is prevented from draining into the internal sump of the anesthetic vaporizer which prevents the wrong anesthetic agent being poured into the vaporizer from an open bottle without the presence of a correct bottle adapter.
In accordance with one aspect of the invention, the filler valve assembly includes a valve body having a conical sealing surface. The conical sealing surface is biased into contact with a seal formed near the bottom edge of the filler body. The interaction between the conical sealing surface of the valve body and the seal provides a liquid-tight seal to prevent anesthetic agent from inadvertently being dispensed into the anesthetic vaporizer.
The filler valve assembly further includes a centrally located stationary activation rod that is immovably located within the filler body, along the centerline of the filling station. The activation rod is secured to a mounting block, which in turn is mounted to the inner surface of the filler body. The mounting block includes a series of cylindrical openings that allow anesthetic agent to flow past the otherwise solid mounting block.
The valve body of the filler valve assembly includes a plurality of projecting legs that each extend through one of the cylindrical openings formed in the mounting block. In this manner, the valve body extends past the stationary mounting block such that the protruding legs and valve body are movable relative to the stationary mounting block and stationary fixed activation rod.
A bias spring is positioned to urge the valve body into contact with the seal to prevent inadvertent filling of the anesthetic vaporizer with a supply of anesthetic agent. As described, the implementation of the fixed activation rod eliminates the dependency on relative spring rates between the movable valve body of the vaporizer and the adapter valve assembly of the bottle adapter.
In accordance with the present invention, the filling system allows the bottle adapter to be securely coupled to the filling station as follows. Initially, the bottle adapter is attached to the correct type of anesthetic bottle. The interaction between the mounting slots formed in the bottle adapter and the protrusions on the anesthetic agent bottle insure that the bottle adapter is used upon only the correct type of anesthetic agent.
Once the bottle adapter has been installed, the bottle adapter is brought into engagement with the filling station. As the bottle adapter is inserted into the filling station, the indexing ridges on the bottle adapter are brought into engagement with the indexing grooves formed in the filling station. If the indexing grooves and indexing ridges match, the bottle adapter can be fully inserted into the filling station as will be described. However, if the indexing grooves do not match the indexing notches, the bottle adapter is prevented from fully entering into the filling station.
If the bottle adapter is correct for the anesthetic vaporizer, the bottle adapter is inserted further into the filling station. As the bottle adapter is inserted, the sealing ring formed around the probe section of the bottle adapter engages a smooth inner surface formed within the filler body of the filling station. The interaction between the sealing ring and the smooth inner surface provides a gas-tight seal to prevent built-up gas within the anesthetic vaporizer from being released to atmosphere.
As the bottle adapter is moved further into engagement with the filling station, the top lip of the bottle adapter contacts the projecting legs formed on the valve body of the filler valve assembly. Slightly further movement of the bottle adapter causes the bottle adapter to move the valve body away from the seal and open the filler valve assembly.
In another aspect of the invention, the dimensions of the bottle adapter and filling station are selected such that when the bottle adapter initially opens the filler valve assembly, the top end of the stationary activation rod is spaced slightly from a recessed face surface formed on the valve head of the adapter valve assembly. Thus, the filler valve assembly opens prior to opening of the adapter valve assembly.
Further movement of the bottle adapter into the filling station results in the stationary activation rod moving the valve head of the adapter valve assembly to an open position. When in the open position, anesthetic agent can flow through the bottle adapter and into the filling station.
As can be understood by the above description, the sealing ring formed around the bottle adapter provides for a gas seal prior to opening of either the adapter valve assembly or the filler valve assembly. Additionally, the interaction between the keyed section of the bottle adapter and the filler spout of the filling station insure the proper type of anesthetic agent is being dispensed prior to opening of either valve assembly within the filling system
If the correct bottle adapter is being used, the invention insures that the filler valve assembly opens prior to the adapter valve assembly such that any discharged anesthetic agent is able to flow into the anesthetic vaporizer.
In accordance with yet another aspect of the present invention, the stationary activation rod can include an internal passageway having a first opening and a second opening. The first and second openings of the activation rod are positioned on opposite sides of the seal created by the valve body. This establishes a vent path to the sump for draining of anesthetic agent from the vaporizer such that with the drain plug opened, and the filler cap loosened, venting of the sump is accomplished, facilitating drainage.
In another aspect of the invention, the anesthetic vaporizer can include a colored indicator mark, label, feature or cover near the filling station that indicates the type of anesthetic agent to be dispensed into the vaporizer. The color of the indicating mark on the anesthetic vaporizer directly corresponds to the color of the bottle adapter to be used with the correct type of anesthetic agent. The positioning of such colored marks, features or components directly adjacent to the filler is chosen to present to the operator a direct color contrast with the bottle adapter in the event that the incorrect adapter is offered up to the vaporizer filler.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.